Method of preparing oil-soluble sulfonates



Aug. 31, 1948. N. E. LEMMON METHOD 0F PREPARING OIL-SOLUBLE SULFONATES Filed Dec. 22, 1944 MPL .$6 um -to the large treating losses, it is difllcult to4 ob- Patented Aug. 3l, 1948 ramon or' vasellame tin-somma SULFONATES Norman E. Lemmon, Hammond, lind., or to Standard Oil Company, Chicago, lill., a corporation of Indiana Application December 22, 1944, Serial No. 569,410

l 6 Claims. (Ci. i860-505) This invention relates to improvements in the method of preparing preferentially oil-soluble sulfonic acids and sulfonates and more partielllarly relates to an improved process for the preparation of synthetic preferentially oil-soluble sulfonic acids and sulfonates resulting from the sulfonation of alkylated aromatic hydrocarbons.

Sulfonated alkyl aromatic hydrocarbons have been widely used as wetting, washing, emulsifying and detergent agents. Depending upon the length of the alkyl chain of the alkyl substituent. the sulfonated alkyl aromatic hydrocarbons are either preferentially water-soluble or preferentially oil-soluble. For example, alkyl benzene sulfonates in which the alkyl group contains from about 1D to about 5 carbon atoms are pre'ferentially water-soluble and are useful as wetting and/or detergent agents. 'I'he higher alkyl benzene sulfonates. that'is, alkyl benzene sulfonates containing more than 16 carbon atoms and usually from about 18 to about 30 carbon atoms in the alkyl groups,` are preferentially cilsoluble. These preferentially oil-soluble alkyl aromatic sulfonates in many respects resemble the preferentially oil-soluble sulfonates obtained in the treatment of petroleum oils with concentrated or fuming sulfuric acid. These preferentially oil-soluble petroleum sulfonates, because of their characteristic color are generally referred to as mahogany soapsA although certain preferentially oil-soluble petroleum sulfonates having a characteristic brownish color are called brown acid soaps.

The alkylated aromatics containing from about 10 to about 15 carbon atoms in the alkyl chain are selectively sulfonated with from about 88% to 'about 98% sulfuric acid. 'Ihe sulfonates so obtained are of the preferentially water-soluble type andare separated from the unreacted higher allwlated aromatics by stratification or other' suitable means. Heretofore the higher alkylated aromatics have been sulionated to obtain preferentially oil-soluble sulfonates by treatment with sulfuric acid of from about 98% to about 1041/296 strength. Large treating losses are obtained by this process since it is extremely dil!!- cult to separate the spent acid from the sulfonated higher alkylated aromatics. In addition sulfonates. Another object of the invention is to provide an improved method of obtaining low inorganic' salt content, preferentially oil-soluble alkylated aromatic sulfonic acids and sulfonates having more than 17 carbon atoms in the alkyl chain. Another object of my invention is to provide an improved method of sulfonating alkyl aromatics having more than 17 carbon atoms in the alkyl chain whereby a product having a low inorganic sait contents is obtained. Other objects and advantages of the present invention will become apparent from the following description thereof, read in conjunction with the accompanying drawing, which is a schematic ow diagram of a preferred method of carrying out the invention, and which forms a part of this specification. l

In accordance with the present invention alkylated aromatic hydrocarbons having at least 18 carbon atoms in the alkyl chains and preferably from about 18 to 30 or more carbon atoms in the alkyl chains, are sulfonated by reaction with sulfur trioxide at a temperature of from about 50 F. to about 200 F. and preferably from about 75 F. to about 175 F. in an atmosphere of nitrogen or air for a period suillcient to permit substantially complete sulfonation of the alkylated aromatic. Depending upon the temperature employed, the reaction period can range from about minutes to about 60 minutes or more. By employing sulfur trioxide as the sulfonating agent in place of the usual concentrated or fuming sulfuric acid, 4the resultant preferentially oil-soluble sulfonic acids or sulfonates are substantally free of contamination with sulfuric acid. The small amount of sulfuric acid resulting from the react-ion of water and SO: which may be occluded in the sulfonate can be readily removed by 4contacting the sulfonic acids with clay, as more fully hereinafter described.

The present invention can be applied to a wide variety of alkyl aromatic compounds in which the alkyl substituent has at least 18 carbon atoms in the chain. The aromatic nucleus can be, for example. benzene, toluene, xylene, cumene, naphthalene, methyl naphthalenes, ethyl naphthalenes, isopropyl or alkyl naphthalenes, diphenyl, alkyl phenyls, anthracene, and alkyl anthracene. Halogen, nitro, hydroxy or other derivatives of the aromatic hydrocarbons can also be sulfonated in accordance with the present invention.

The aromatic nucleus may be alkylated to produe alkylated aromatics having at least 18 carbon atoms in the allwl chain or the aromatic tain a purified sulfonate having a low inorganic salt content.

It is an object of this invention to provide an improved method. of preparing preferentially oil-soluble alkylated aromatic sulfonic acids and ranges.

nucleus may be alkylated with a mixture of alkylating agents wherein the length of the alkyl group can'vary from those having less than 18 carbon atoms and those having at least 18 carbon atoms. When the alkylated aromatic compound contains mixtures of alkyl substituents in which the length of the alkyl group varies from those having less than 18 carbon atoms and those having at least 18 carbon atoms, alkymers having at least 18 carbon atoms can be segregated from such mixture by several suitable means. For example, the mixture of alkymers may be subjected to fractional distillation to obtain a suitable material having at least 18 carbon atoms in the alkyl chain or the mixture of alkymers may be selectively sulfonated as hereinafter-described. The alkylating agents may be haloparafi'ins, olelins, oleiln polymers, alkyl sulfates, aliphatic alcohols or aliphatic esters of wide molecular weight range.

The alkylation of the aromatic compound by alkylating agents of the foregoing type can be accomplished by reacting the aromatic and the alkylating agent in the presence of 90% to 100% sulfuric acid, aluminum chloride, preferably activated with a trace of hydrogen'chloride. hydrogen fluoride, boron fluoride, mixtures of hydrogen fluoride and boron fluoride or other known alkylation catalysts.

Suitable alkylating agents are olefin polymers, particularly those of ethylene, propylene, butylenes, amylenes and the like or mixtures thereof, preferably those having at least about 18 carbon atoms in the chain and preferably from about 18 to about 30 carbon atoms in the alkyl chain. Suitable oleiin polymers are those having a distillation range of from about 220 F. to about 500 F. at 5 mm. Propylene polymers vand butylene polymers of at least about 18 carbon atoms are especially suitable as alkylating agents for the aromatic hydrocarbons. Butylene and propylene polymers having an initial boiling point of at least about 230 F. at 5 mm. are especially well adapted for the alkylation of the aromatic hydrocarbons.' Propylene can be polymerized by passing it in the liquid phase through a pool of dispersed aluminum chloride catalyst to yield a polymer of relatively wide boiling and molecular weight While the total polymer -may be employed in the alkylation of the aromatic hydrocarbon, it is preferred to fractionate the polymer to remove a fraction boiling below about 230 F. at 5 mm. and corresponding to polymers of less than 18 carbon atoms. The residuum comprising polymers boiling above about 230 F. at 5 mm. and of at least 18 carbon atoms can then be used as the alkylating agent in the alkylation of a desred aromatic compound. for example benzene, toluene and the like. These higher alkymers are then sulfonated with sulfur trioxide in the manner hereinafter-described.

Alternatively the aromatic compound can be alkylated with the total polymer and the alkymer selectively sulfonated by treatment with sulfuric acid of from about 88 to 98 weight percent strength at a temperature in the approximate range of from about 50 F. to about 150 F. The initial sulfuric acid strength and other reaction nditions are adjusted and selected to eii'ect the selective sulfonation only of those alkyl aro-` matics whose monosuli'onic acids are preferentially water-soluble. From about 0.2 to about 2 volumes of acid per volume of alkylated aromatic are suitably employed andthe reaction time can vary from about 1 to about 20 hours 0r mOle 1.1-

pending upon the nature of the specific feed stock, acid strength and other reaction conditions. The selective sulfonation depends upon the proper strength and vamount of sulfuric acid. For example, in the sulfonation of alkyl benzenes it is essential that the acid strength be suchl that only alkyl benzenes containing less than about 18 carbon atoms in the alkyl group are sulfonated. It is likewise important that the amount of acid be sufficient so that the spent acid is of sufficient strength to retainin solution the alkyl benzene sulfonic acid containing less than about 9 carbon atoms in the alkyl group. After completion 'of the selective sulfonation the reaction products f can be separated by a variety of methods such as. for example; by solvent extraction, dilution with water and stratification. it is preferable; lhowever, to allow the reaction mixture to stratify without the addition of water or other diluting media. Generally three strata are obtained, the lowest stratum comprising essentially spent suifuric acid and alkyl aromatic sulfonic acids fin which the aikyl group contains less than 8 carbon atoms. The middle stratum comprises predominantly the alkyl aromatic sulfonic acids of from about 9 to about 17 carbon atoms in the alkyl .group which are preferentially water-soluble.

The upper stratum comprises predominantly unsulfonated alkyl aromatics in which the alkyl groups contain at least 18 carbon atoms. Upon segregation of the various strata, the upper stratum constitutes the starting material for the sulfonation of preferentially oil-soluble sulfonic acid compounds prepared as hereinafter-described.

As mentioned above, the present invention is applicable to the sulfonation of higher alkylated aromatics in which the alkylation is brought about by means of alkylating agents other than olefin polymers. For example, the non-aromatic hydnocarbons may be converted to suitable al`- kylation form in various ways. For example Ihalogenated paraiiin hydrocarbons having the proper distillation characteristics can be employed in the manner described in U. S. Patent 2,233,408 issued to L. H. Flett on March 4, 1941-.

The present invention will be clearly understood from the following description thereof read in conjunction with the accompanying drawing. Referring to the drawing, olefin polymers such as butylene polymers or propylene polymers of from.

about 9 to about 30 or more carbon atoms are introduced from a storage tank I through line! to an alkylation zone 3. Aluminum chloride, anhydrous HC1 and an aromatic hydrocarbon such as toluene are introduced into alkylation zone 3 through a line 4. Alkylation ofthe aromatic takes place in the alkylation zone 3 at a temperature of about F. Light ends are removed from the allqvlation zone 3 and removed overhead through a line 5 and an aluminum complex is withdrawn from the zone 3 through a line 8. Ihe alkylated aromatics hereinafter referred to as the alkymer are withdrawn from the alkylation 'zone 3 through a linel l and introduced into a reactor 8 wherein-it is treated with sulfuric acid of from about 88% to about 98% strength. introduced through a line 8 and the alkymer having from about 9 to about 17 carbon atoms in the alkyl groups selectively sulfonated. After this selective sulfonation the reaction mixture is permitted to stratify into a lower layer comprising essentially spent sulfuric acid and alkyl -aromatic sulfonic acids having less than 9 carbon atoms in the alkyl group, which are withdrawn'from the reactor 8 altares y s e throughaline ilzamlddielayercomprising predominantb' sulfouatedr alkymers having from abouttoa'bout 17 carbon 'atomsin'thealkyl group whichare withdrawn from the reactor I throughalineilzandanupperlayercomprising r'predominantly unsulfonated alkymen inf which thealk'yl groups contain more than about 17 carbon atoms. This upper layer is withdrawn from vthe're'actor I through a line l2 and intro-- duced into a reactor il wlerein itis sulfonated by treatment with SO.:v introduced through a line it. Preferably the s'ulfonation in reactor Il takes place in an atmosphere of nitrogen or air introduced through a linel Il. Bulfonation of the alkym'er in reactoril `is carried out at a temperature of from about 50 F. to about 200 F. and preferably at a temperature of about. 176 1".

.. Upon completion of the summation reaction the sulfonic acidsformed are blown free of 80: and

1nnreacted B0: byI blowing with air or nitrogen introduced through line il. the gases being removed from the reactor through vent l1. Ihe

. with from about 1% to about 3% of an adsorp- 1 tion clay Vat a temperature of from about 100 F. to about 200 F. to substantially completely remove the sulfuric acid contained in the sulfonic acids. The mixture of sulfonic acids and clay is The.

, 6 y f resulting from ther reaction of water. This product was diluted.y with an equal volume of a refined white oil and contactedwith 1% of an adsorbent clay. The product was then filtered.w`

carefully neutralized withsodium hydroxide kand the water removed therefrom by distillation.v

The following data represent the yield andthe weight balance based on the higher alkymer used, obtainedin the above example:

. Grams Weight of alkymer charged 100 Weight'of alkymer sulfonated s 80.89 Weight of alkymer sulfonate recovered 85.80

Weight of alkymer lost 7.7

then passed through line 2l to a nlter press 2l to remove the clay, and the filtrate of oil diluted sulfonic acids substantially free of sulfuric acids withdrawn from the illter 2l through line 2B and introduced into a Ireactor 20 wherein it is neutralized with caustic soda introduced into the reactor 2O through line 21. .After the neutralization is completed water is removed from reactor through line 28. the neutralized product brightened by air blowing. and the oil solution of sodium sulfonates having a low salt content removed through line 2l to suitable storage (not shown).

'Ihe present invention may be clearly understood from the following specific example which is given by way of illustration only and is not intended to be considered as a limitation of the invention. An alkylated benzene obtained by alkylating benzene with a propylene polymer Weight of alkyrner lost after neutralization Weight of SO: added 26.8 Weight of B0: converted to sulfonate 16.0

The apparent high loss after neutralization was due to the presence of some low boiling materials lin the alkymer which were evaporated off on removal of water from the recovered sulfonate. Thef-sulfonate recovered showed the following analysis based on a 1:1 dilution with white o8:

f Per cent Oil 48.9 Soap l 43.4 Salts 2.9

The salt content of preferentially oil-solubley sulfonates obtained by treating alkylated al'omatics` with 18 or more carbon atoms in the alkyl groups in the conventional manner, that is. with fuming sulfuric acid, is generally of the order of magnitude of about 10% or even greater. Such' a product would need to be desalted and considerable loss of soap would result in this operation.

While I have described my invention by reference to specific embodiments thereof, the invention is not intended to be limited thereto but inoludes within its scope such modifications as come within the spirit of the appended claims.

having a distillation range of from about 100 F.

to about 430 F. at 5 mm. and comprising substantially a mixture of C to Cao, or more aliphatic hydrocarbons was sulfonated by treatment with 96% sulfuric acid at a temperature of about 80 l". for about 10 hours. The sulfonic acids resulting from this sulfonation step comprised essentially of preferentially water-soluble alkyl aromatic sulfonic acids having less than about 18 carbon atoms in the alkyl chain. were separated from the unsulfonated portion by decantation. The unsulfonated higher alkylated benzene was washed with alcohol and then treated with sulfur trioxide at a temperature of 175 F. for 30 minutes in an atmosphere of nitrogen. The product obtained ,comprised essentially higher alkylated benzene sulfonic acids which were preferentially oil-soluble and which contained only a very small amount of sulfuric acid I claim:

1. The method of preparing a preferentially oil-soluble alkylated aromatic sulfonate comprising sulfonating van alkylated aromatic hydrocarbon having at least 18 carbon atoms in the alkyl group with sulfur trioxide, blowing the sulfonated alkylated aromatic hydrocarbon with a gas to remove SO: and S03, contacting the blown alkylated aromatic sulfonic acid with a small amount of an adsorption clay, whereby an alkylated aromatic sulfonic acid substantially free of sulfuric acid is obtained, and neutralizing said clay-contacted alkylated aromatic sulfonic acid whereby a preferentially oil-soluble alkylated aromatic sulfonate having a relatively low inorganic sulfate content is obtained.

2. The method of preparing a preferentially oil-soluble allwlated aromatic sulfonate comprising treating an alkylated aromatic hydrocarbon containing at least 18 carbon atoms in the alkyl group with sulfur trioxide, blowing the alkylated aromatic sulfonic acid formed to remove SO: and $0.1. diluting the blown alkylated aromatic sulfonic acid with a hydrocarbon oil, contacting the diluted blown alkylated aromatic sulfonic acid with an adsorption clay. and neutralizing said clay-contacted oil solution of alkylated aromatic sulfonic acid whereby a preferentially oil-soluble alkylated aromatic sulfonate substantially free of inorganic sulfates is obtained.

3. The method of preparing a preferentially oil-soluble polyolen alkylated benzene sulfonate comprising 'treating a polyolenn alkylated ben- Y zene containing at least 18 carbon atoms in the drocarbon oil, diluting said diluted sulfonic acid with 'an adsorption clay, separating the diluted sulfonic acid from said adsorption clayand neutralizing the clay-contacted oil solution of said polyolefin aikylated benzene sulfonicacid, whereby a preferentially oilsolub1e, polyoleiln alkylated benzene sulfonate substantially free ot inorganicsulfates is obtained.

4. The method of preparing preferentially* oilsoluble alkylated aromatic suifonates comprising suli'onating alkylated aromatic hydrocarbons containing .more than 18 carbon atoms in., the alkyl groupwith sulfur trioxide at a temperature of from about 50 F.- to about 200 F., blowing the resultant alkylated aromatic sulfonic acids to remove SOa and S03 therefrom, diluting the blown alkylated aromatic sulfonic acids with a hydrocarbon oil, contacting the oil solution .of albwlated aromatic' sulfonic acids with an adsorptionolay at a temperature otabout100 to 200 F., separating the clay from the alkylated aromatic sul- Ionic acids and neutralizing the clay-contacted alkyiated aromatic sulfonic acids with caustic, wherebypreferentially oi1-soluble alkylated aromatie sulfonates substantially free of inorganic sulfates are obtained.

5. The method of clai m4, in which the diluted blown alkylated aromatic sulfonic acids-are contacted with from about 1% to. about 3% of an adsorption clay.

6. The method of preparing a preferentially l oli-soluble alkylated aromatic sulfonate comprising treating analkylated aromatic hydrocarbon having atleast 18 carbon atoms in the 5 alkyl group with sulfur trioxide, blowing the resultant alkylated .aromatic sulionic acid toremove- B0: and SO: therefrom, and neutralizing the blown alkylated aromatic sulionic acid to obtain an alkylated aromatic sulfonate having a =10 relatively low inorganic sulfate content.

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